ES2376919T3 - Multilayer resin coated sand - Google Patents

Abstract

A particulate material comprising: - a particulate substrate coated with a first layer comprising a first thermoplastic polymer and a second layer comprising a second thermoplastic polymer; - wherein the melting point of the first thermoplastic polymer is greater than the melting point of the second thermoplastic polymer.

Description

Sand coated with multi-layer resin

BACKGROUND OF THE INVENTION

Field of the Invention

5 The embodiments described herein generally refer to polymer-coated particulate materials. In another aspect, the embodiments described herein refer to a process for producing polymer-coated particulate materials. In more specific aspects, the embodiments described herein refer to particulate materials such as polymer coated sands, where the sands or other particulate materials can be coated or incorporated with one or more layers of a polymer or

10 polymer mixture.

Background

The artificial grass consists of a multitude of tufts of artificial grass that extend upwards from a laminate substrate. The filler material dispersed between the artificial grass plumes keeps the artificial grass plumes in a state in an upright position, preventing them from laying flat or in another undesirable way.

Several different materials have been used as filler, including silica sand coated with an elastomeric material, as described in US Pat. No. 5,043,320. In Patent No. 5,043,320, the filler granules are formed by mixing silica sand and an aqueous emulsion of a synthetic rubber. The sand is preheated to 140 ° C and the mixture is kept at a temperature above 100 ° C to evaporate the water, producing a dry coating on each grain of sand.

20 As another example of materials used as filler, US Patent Application Publication. No. 20060100342 describes filler formed by coating silica sand with elastomeric materials or thermoplastic polymers. Filler granules are formed by first heating a part of the silica at a temperature between 200 ° C and 300 ° C, placing the sand in a mixer and adding elastomeric or thermoplastic polymer pellets while mixing. Then the thermoplastic polymer melts, coating the sand. After the

The contents of the mixture are cooled using a water and air sprayer that flows through the mixer. The exact amount and time of spraying with water are critical to produce a good creep material without significant formation of agglomerates.

As a third example of materials used as fillers, the publication of US patent application. No. 20050003193 describes filling granules formed by coating a core of pneumatic material

30 recycled with a plastic. The filling granules are formed by mixing the plastic and the recycled tire granules, melting the plastic, and laminating the mixture to form sheets. The sheets are cooled, solidifying the plastic, and then the sheets are subjected to granulation, resulting in recycled tire granules coated with plastic, for use as a filler.

The choice of the filling material, core and coating can greatly influence the general characteristics of the

35 artificial grass. It is convenient to have a padding that has a homogeneous and complete coating, which results in both good appearance and good wear resistance. It is also convenient for the filling to have good sliding and thermal resistance for long-term use and avoid compaction in the filling. The padding should have a soft coating, which provides the desired haptic (sensation), aesthetics and safety of the player, and it is necessary that the padding has good creep to facilitate application.

40 Filler materials produced as described in the patents and publications referred to above, often produce fillers that do not have a good balance of the desired properties. In addition, the procedures used may be ineffective, produce an incomplete coating of the granular material or produce an excess of agglomerates.

Therefore, improvements in the procedures used to produce the filling are necessary. It is convenient

45 have a procedure that provides a lower cost with less waste. It is also convenient to have a resin that provides a homogeneous and uniform coating, which of superior wear resistance, good haptic and aesthetic, and excellent player safety. Improvements in the resulting properties and the general balance of the filling properties are also necessary.

The invention provides a particulate material having: a particulate substrate coated with a first

50 layer comprising a first thermoplastic polymer and a second layer comprising a second thermoplastic polymer; wherein the melting point of the first thermoplastic polymer is greater than the melting point of the second thermoplastic polymer.

In one aspect, the embodiments described herein refer to polymer-coated particulate materials. In more specific aspects, the embodiments described herein refer to

particulate materials such as polymer coated sands, where the sands or other particulate materials may be coated or incorporated with one or more layers of a polymer or polymer blend.

Particulate materials

The particulate materials to be coated with a polymeric lacquer, in some embodiments, may include mineral grains and sands. In other embodiments, the particulate materials may include silica-based sands, such as quartz sands, white sands, such as limestone-based sands, arkosa, and sands containing magnetite, chlorite, glauconite or gypsum. In other embodiments, the mineral grains may include different fillers, such as calcium carbonate, talc, glass fibers, polymeric fibers (including nylon, rayon, cotton, polyester and polyamide) and metal fibers. In other embodiments, the particulate materials to be coated may include rubber particles, including recycled tire.

Mineral grains and sands may have a size in the range of 0.1 to 3 mm in some embodiments. In other embodiments, mineral grains and sands may have a size in the range of 0.2 to 2.5 mm; from 0.3 to 2.0 mm in other embodiments; and from 0.4 to 1.2 mm, in other embodiments.

Polymer

The polymeric resin used to coat the particulate material may vary depending on the particular application and the desired result. In one embodiment, for example, the polymeric resin is an olefinic polymer. As used herein, an olefinic polymer refers, in general, to a class of polymers formed from hydrocarbon monomers having the general formula CnH2n. The olefinic polymer may be present as a copolymer, such as an interpolymer, a block copolymer or a multi-block interpolymer or copolymer.

In a particular embodiment, for example, the olefinic polymer may comprise an alpha-olefinic interpolymer of ethylene with at least one comonomer selected from the group consisting of a linear, branched or cyclic C3-C20 diene, or a vinyl ethylene compound, such as vinyl acetate, and a compound represented by the formula H2C = CHR wherein R is a linear, branched or cyclic C1-C20 alkyl group or a C6-C20 aryl group. Examples of comonomers include propylene, 1-butene, 3-methyl-1-butene, 4-methyl-1-pentene, 3-methyl-1-pentene, 1-heptene, 1hexene, 1-octene, 1-decene and 1 -dodecene.

In other embodiments, the thermoplastic resin may be an alpha-olefinic propylene interpolymer with at least one comonomer selected from the group consisting of ethylene, a linear, branched or cyclic C4-C20 diene, and a compound represented by the formula H2C = CHR in which R is a linear, branched or cyclic C1-C20 alkyl group

or a C6-C20 aryl group. Examples of comonomers include ethylene, 1-butene, 3-methyl-1-butene, 4-methyl-1pentene, 3-methyl-1-pentene, 1-heptene, 1-hexene, 1-octene, 1-decene, and 1-dodecene. In some embodiments, the comonomer is present in about 5% by weight to about 25% by weight of the interpolymer. In one embodiment, a propylene-ethylene interpolymer is used.

Other examples of thermoplastic resins that can be used in the present description include homopolymers and copolymers (including elastomers) of an olefin such as ethylene, propylene, 1-butene, 3-methyl-1-butene, 4-methyl1-pentene, 3- methyl-1-pentene, 1-heptene, 1-hexene, 1-octene, 1-decene, and 1-dodecene, typically represented by polyethylene, polypropylene, poly (1-butene), poly (3-methyl-1-butene ), poly (3-methyl-1-pentene), poly (4-methyl-1-pentene), ethylene-propylene copolymer, ethylene-1-butene copolymer and propylene-1-butene copolymer; copolymers (including elastomers) of an alpha-olefin with a conjugated or unconjugated diene, typically represented by ethylene-butadiene copolymer and ethylene-ethylidenebornene copolymer; and polyolefins (including elastomers) such as copolymers of two or more alpha-olefins with a conjugated or unconjugated diene, typically represented by ethylene-propylene-butadiene copolymer, ethylene-propylene-dicyclopentadiene copolymer, ethylene-propylene-1 copolymer , 5-hexadiene and ethylene-propylene-ethylideneborborne copolymer; ethylene-vinyl compound copolymers such as ethylene-vinyl acetate copolymers with N-methylol functional comonomers, ethylene-vinyl alcohol copolymers with N-methylol functional comonomers, vinyl ethylene chloride copolymer, ethylene-acrylic acid copolymers or ethylene (meth) acrylic acid and copolymer of ethylene (meth) acrylate; styrene copolymers (including elastomers) such as polystyrene, ABS, acrylonitrile-styrene copolymer, methyl styrene-styrene copolymer; and styrene block copolymers (including elastomers) such as styrene-butadiene copolymer and hydrates thereof, and styrene-isoprene-styrene triblock copolymer; polyvinyl compounds such as polyvinyl chloride, polyvinylidene chloride, vinylchloride vinylidene chloride copolymer, poly (methyl acrylate), and poly (methyl methacrylate); polyamides such as nylon 6, nylon 6.6, and nylon 12; thermoplastic polyesters such as poly (ethylene terephthalate) and poly (butylene terephthalate); polycarbonate, poly (phenylene oxide), and the like. These resins can be used alone or in combinations of two or more.

In particular embodiments, polyolefins such as polypropylene, polyethylene, and copolymers thereof and mixtures thereof, as well as ethylene-propylene-diene terpolymers can be used. In some embodiments, olefinic polymers include homogeneous polymers described in US Pat. No. 3,645,992 to Elston; high density polyethylene (HDPE) as described in US Pat. No. 4,076,698 to Anderson;

heterogeneously branched linear low density polyethylene (LLDPE); linear ultra-low density branched heterogeneously (ULDPE); linear ethylene / alpha-olefin copolymers, homogeneously branched; substantially linear ethylene / alpha-olefin polymers, homogeneously branched, which can be prepared, for example, by a process described in US Pat. No. 5,272,236 and 5,278,272, heterogeneously branched linear ethylene / alpha-olefin polymers; and polymers and copolymers of high-pressure free radical polymerized ethylene, such as low density polyethylene (LDPE).

In another embodiment, the thermoplastic resin may include an ethylene-carboxylic acid copolymer, such as ethylene-vinyl acetate (EVA) copolymers, ethylene-acrylic acid (EAA) and ethylene-methacrylic acid copolymers, such as, for example , those available under the trade names PRIMACORT of The Dow Chemical Company, NUCRELT of DuPont, and ESCORT of ExxonMobil, and described in US Pat. No. 4,599,392, 4,988,781 and 5,384,373.

Example polymers include polypropylene, (both impact modified polypropylene, isotactic polypropylene, atactic polypropylene, and random ethylene / propylene copolymers), different types of polyethylene, including high-pressure free radical LDPE, Ziegler Natta LLDPE, PE based in metallocenes, including multiple reactor PE ("inside the reactor"), mixtures of Ziegler-Natta PE and metallocene based PE, such as the products described in US Pat. No. 6,545,088, 6,538,070, 6,566,446, 5,844,045, 5,869,575 and

6,448,341. In some embodiments, homogeneous polymers such as olefinic elastomers and elastomers, copolymers based on ethylene and propylene (for example, polymers available under the trade name VERSIFYT available from The Dow Chemical Company and VISTAMAXXT available from ExxonMobil) may also be useful. Of course, mixtures of polymers can also be used. In some embodiments, the mixtures include two different Ziegler-Natta polymers. In other embodiments, the mixtures may include mixtures of a Ziegler-Natta polymer and one based on metallocenes. In yet other embodiments, the thermoplastic resin used herein may be a mixture of two polymers based on different metallocenes.

In a particular embodiment, the thermoplastic resin may comprise an alpha-olefinic ethylene interpolymer with a comonomer comprising an alkene, such as 1-octene. The ethylene and octene copolymer may be present alone or in combination with another thermoplastic resin, such as ethylene-acrylic acid copolymer. When present together, the weight ratio between the ethylene-octene copolymer and the ethylene-acrylic acid copolymer may be from about 1:10 to about 10: 1, such as from about 3: 2 to about 2: 3 . The polymeric resin, such as the ethylene-octene copolymer, may have a crystallinity of less than about 50%, such as less than about 25%. In some embodiments, the crystallinity of the polymer may be 5 to 35 percent. In other embodiments, the crystallinity may be in the range of 7 to 20 percent.

The embodiments described herein may also include a polymer component that may include at least one multi-block olefinic interpolymer. Suitable multi-block olefinic interpolymers may include those described in the US provisional patent application. NO 60 / 818,911, for example. The term "multiblock copolymer" refers to a polymer comprising two or more chemically distinct regions or segments (called "blocks") preferably linearly bonded, that is, a polymer comprising chemically distinct units that are end-to-end bonded. extreme with respect to the polymerized ethylene functional group, rather than in a pendant or grafted form. In some embodiments, the blocks differ in the amount or type of comonomer incorporated therein, the density, the degree of crystallinity, the size of the crystallites attributable to a polymer of said composition, the type or degree of tacticity (isotactic or syndiotactic ), regiorregularity or regioregularity, the amount of branching, including long chain branching or hyperbranching, homogeneity or any other physical or chemical property. Multi-block copolymers are characterized by single distributions of the polydispersity index (PDI or Mw / Mn), distribution of block lengths and / or distribution of the number of blocks due to the unique process of making the copolymers. More specifically, when produced in a continuous process, embodiments of the polymers can have a PDI in the range of about 1.7 to about 8; from about 1.7 to about 3.5 in other embodiments; from about 1.7 to about 2.5 in other embodiments; and from about 1.8 to about 2.5, or from about 1.8 to about 2.1, in yet other embodiments. When they occur in a discontinuous or semi-continuous process, embodiments of the polymers can have a PDI in the range of about 1.0 to about 2.9; from about 1.3 to about 2.5 in other embodiments; from about 1.4 to about 2.0 in other embodiments; and from about 1.4 to about 1.8 in other embodiments.

An example of the multi-block olefinic interpolymer is an ethylene / a-olefin block interpolymer. Another example of the multi-block olefinic interpolymer is a propylene / a-olefin interpolymer. The following description focuses on the interpolymer having ethylene as the majority monomer, but is applied in a similar manner to multiblock interpolymers based on propylene, with respect to the general characteristics of the polymer.

The multiblock ethylene / a-olefin interpolymers may comprise ethylene and one or more copolymerizable olefinic comonomers in polymerized form, characterized by multiple (i.e., two or more) blocks or segments of two or more polymerized monomer units, which differ in chemical or physical properties

(block interpolymer), preferably a multi-block interpolymer. In some embodiments, the multi-block interpolymer can be represented by the following formula:

(AB) n

where n is at least 1, preferably an integer greater than 1, such as 2, 3, 4, 5, 10, 15, 20, 30, 40, 50, 60, 70, 80, 90, 100, or higher; "A" represents a hard block or segment; and "B" represents a soft block or segment. Preferably, blocks A and B are connected linearly, not branched or star. "Hard" segments refer to blocks of polymerized units in which ethylene is present in an amount greater than 95 percent by weight in some embodiments, and in other embodiments greater than 98 percent by weight. In other words, the comonomer content in the hard segments is less than 5 percent by weight in some embodiments, and in other embodiments, less than 2 percent by weight of the total weight of the hard segments. In some embodiments, the hard segments comprise all or essentially all ethylene. The "soft" segments, on the other hand, refer to blocks of polymerized units in which the comonomer content is greater than 5 percent by weight of the total weight of the soft segments in some embodiments, greater than 8 percent by weight , greater than 10 percent by weight, or greater than 15 percent by weight, in other different embodiments. In some embodiments, the comonomer content in the soft segments may be greater than 20 percent by weight, greater than 25 percent by weight, greater than 30 percent by weight, greater than 35 percent by weight, greater than 40 percent. percent by weight, greater than 45 percent by weight, greater than 50 percent by weight or greater than 60 percent by weight in other different embodiments.

In some embodiments, blocks A and blocks B are randomly distributed along the polymer chain. In other words, block copolymers do not have a structure like:

AAA-AA-BBB-BB

In other embodiments, block copolymers do not have a third block. In yet other embodiments, neither block A nor block B comprise two or more segments (or sub-blocks), such as an extreme segment.

Multiblock interpolymers can be characterized by an average block index, ABI, in the range of greater than zero to about 1.0 and a molecular weight distribution, Mw / Mn, greater than about 1.3. The average block index, ABI, is the weighted average block index ("BI") for each of the polymer fractions obtained by preparative TREF from 20OC to 110OC, with an increase of 5OC:

in which BIi is the block index for the fraction ia of the multiblock interpolymer, obtained by preparative TREF, and wi is the percentage by weight of the fraction ia.

Similarly, the square root of the second order moment centered on the average, hereinafter referred to as the second weighted average order moment of the block index, can be defined as follows:

For each polymer fraction, BI is defined by one of the following two equations (both give the same BI value):

where TX is the elution temperature of the analytical fractionation by elution by raising the temperature (ATREF) for the fraction (preferably expressed in Kelvin), PX is the molar fraction of ethylene for the 1st fraction, which can be measured by NMR or IR as described below. PAB is the ethylene molar fraction of the complete ethylene / a-olefin interpolymer (before fractionation) that can also be measured by NMR or IR. TA and PA are the elution temperature of the ATREF and the molar fraction of ethylene for the pure "hard segments" (which refer to the crystalline segments of the interpolymer). As an approximation or for polymers in which the composition of the "hard segment" is not known, the values of TA and PA are established from those of the high density polyethylene homopolymer.

TAB is the elution temperature of the ATREF for a random copolymer of the same composition (which has a molar fraction of ethylene PAB) and the same molecular weight as the multiblock interpolymer. The TAB can be calculated from the molar fraction of ethylene (measured by NMR) using the following equation:

wherein a and � are two constants that can be determined by a calibration using a series of well-characterized preparative TREF fractions of a random copolymer of broad composition and / or random copolymers of ethylene with well characterized narrow composition. Note that a and � may vary from one instrument to another. In addition, it may be necessary to obtain an appropriate calibration curve with the composition of the polymer of interest, using appropriate molecular weight and comonomer type ranges for the fractions of preparative TREF and / or random copolymers used to obtain the calibration. There is a slight effect of molecular weight. If the calibration curve is obtained from similar molecular weight ranges, said effect should be basically negligible. In some embodiments, the random ethylene copolymers and / or the preparative random copolymer TREF fractions satisfy the following relationship:

The above calibration equation refers to the molar fraction of ethylene, P, at the elution temperature of the analytical TREF, TATREF, for random copolymers of narrow composition and / or fractions of preparative TREF of random copolymers of wide composition. Txo is the temperature of ATREF for a random copolymer of the same composition and having a molar fraction of ethylene of PX. TXO can be calculated from LnPX = a / TXO +

�. In contrast, PXO is the molar fraction of ethylene for a random copolymer of the same composition and having an ATREF temperature of TX, which can be calculated from Ln Pxo = a / TX + �.

Once the block index (BI) of each fraction of the preparative TREF is obtained, the weighted average block index, ABI, can be calculated for the entire polymer. In some embodiments, the ABI is greater than zero but less than about 0.4 or from about 0.1 to about 0.3. In other embodiments, the ABI is greater than about 0.4 and up to about 1.0. Preferably, the ABI should be in the range of about 0.4 to about 0.7, about 0.5 to about 0.7, or about 0.6 to about 0.9. In some embodiments, the ABI is in the range of about 0.3 to about 0.9, about 0.3 to about 0.8, or about 0.3 to about 0.7, about 0.3 to about 0.6, about 0.3 to about 0.5, or about 0.3 to about 0.4. In other embodiments, the ABI is in the range of about 0.4 to about 1.0, about 0.5 to about 1.0, or about 0.6 to about 1.0, about 0.7 to about 1.0, about 0.8 to about 1.0, or about 0.9 to about 1.0.

Another feature of the multiblock interpolymer is that the interpolymer can comprise at least one fraction of polymer that can be obtained by preparative TREF, in which the fraction has a block index greater than about 0.1 and up to about 1.0 and the polymer It has a molecular weight distribution, Mw / Mn, greater than approximately 1.3. In some embodiments, the polymer fraction has a block index greater than about 0.6 and up to about 1.0, greater than about 0.7 and up to about 1.0, greater than about 0.8 and up to about 1, 0, or greater than about 0.9 and up to about 1.0. In other embodiments, the polymer fraction has a block index greater than about 0.1 and up to about 1.0, greater than about 0.2 and up to about 1.0, greater than about 0.3 and up to about 1, 0, greater than about 0.4 and up to about 1.0, or greater than about 0.4 and up to about 1.0. In yet other embodiments, the polymer fraction has a block index greater than about 0.1 and up to about 0.5, greater than about 0.2 and up to about 0.5, greater than about 0.3 and up to about 0 , 5, or greater than about 0.4 and up to about 0.5. In yet other embodiments, the polymer fraction has a block index greater than about 0.2 and up to about 0.9, greater than about 0.3 and up to about 0.8, greater than about 0.4 and up to about 0 , 7, or greater than about 0.5 and up to about 0.6.

The multiblock ethylene / a-olefin interpolymers used in the embodiments of the invention may be interpolymers of ethylene with at least one C3-C20 a-olefin. The interpolymers may also comprise a C4-C18 diolefin and / or alkenylbenzene. Suitable unsaturated comonomers useful for polymerizing with ethylene include, for example, ethylenically unsaturated monomers, conjugated or unconjugated dienes, polyenes, alkenylbenzenes, etc. Examples of such comonomers include C3-C20 a-olefins such as propylene, isobutylene, 1-butene, 1-hexene, 1-pentene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-nonhene, 1-decene, and the like. 1-Butene and 1-octene are especially preferred. Other suitable monomers include styrene, halogen or alkyl substituted styrenes, vinylbenzocyclobutane, 1,4-hexadiene, 1,7-octadiene, and naphthenics (such as cyclopentene, cyclohexene and cyclooctene, for example).

The multi-block interpolymers described herein can be distinguished from conventional random copolymers, physical polymer blends and block copolymers prepared by addition.

sequential monomers, fluxional catalysis and anionic or cationic living polymerization techniques. In particular, in comparison with a random copolymer of the same monomers and of the same monomer content for equivalent crystallinity or module, the interpolymers have better (greater) heat resistance measured by their melting point, higher penetration temperature by TMA, greater resistance to high temperature traction and / or greater high temperature torsion storage module, determined by dynamic mechanical analysis. The properties of the filler can benefit from the use of multiblock interpolymer embodiments, compared to a random copolymer containing the same monomers and monomer contents, the multiblock interpolymers have a permanent deformation by lower compression, in particular at elevated temperatures, relaxation of lower stress, greater deformation resistance, greater tear resistance, greater blocking resistance, faster structuring due to a higher crystallization (solidification) temperature, greater recovery (in particular at elevated temperatures), better abrasion resistance, greater retraction force and better acceptance of oils and fillers.

Other olefinic interpolymers include polymers comprising aromatic monovinylidene monomers including styrene, o-methyl styrene, p-methyl ester, t-butyl styrene and the like. In particular, interpolymers comprising ethylene and styrene can be used. In other embodiments, copolymers comprising ethylene, styrene and a C3-C20 α-olefin, optionally comprising a C4-C20 diene, can be used.

Suitable non-conjugated dienes monomers may include a straight chain, branched or cyclic hydrocarbon diene having 6 to 15 carbon atoms. Examples of suitable unconjugated dienes include, but are not limited to, straight chain acyclic dienes, such as 1,4-hexadiene, 1,6-octadiene, 1,7-octadiene, 1,9-decadiene, branched-chain acyclic dienes , such as 5-methyl-1,4-hexadiene; 3,7-dimethyl-1,6-octadiene; 3,7-dimethyl-1,7-octadiene and mixed isomers of dihydromyricene and dihydroocinen, single ring alicyclic dienes, such as 1,3-cyclopentadiene; 1,4-cyclohexadiene; 1,5-cyclooctadiene and 1,5-cyclododecadiene, and dienes with bridged rings and multi-ring alicyclic condensates, such as tetrahydroindene, methyltetrahydroindene, dicyclopentadiene, bicyclo- (2,2,1) -hepta-2,5-diene; alkenyl-, alkylidene-, cycloalkenyl- and cycloalkylene-norbornene, such as 5-methylene-2-norbornene (MNB); 5-propenyl-2-norbornene, 5isopropylidene-2-norbornene, 5- (4-cyclopentenyl) -2-norbornene, 5-cyclohexylidene-2-norbornene, 5-vinyl-2-norbornene, and norbornadiene. Of the dienes typically used to prepare EPDMs, particularly preferred dienes are 1,4-hexadiene (HD), 5-ethylidene-2-norbornene (ENB), 5-vinylidene-2-norbornene (VNB), 5-methylene -2-norbornene (MNB) and dicyclopentadiene (DCPD).

A class of desirable polymers that can be used in accordance with embodiments described herein include elastomeric interpolymers of ethylene, a C3-C20 α-olefin, especially propylene, and optionally one or more diene monomers. Preferred a-olefins for use in this embodiment are designated by the formula CH2 = CHR�, in which R� is a linear or branched alkyl group of 1 to 12 carbon atoms. Examples of suitable a-olefins include, but are not limited to, propylene, isobutylene, 1-butene, 1-pentene, 1hexene, 4-methyl-1-pentene and 1-octene. A particularly preferred a-olefin is propylene. Propylene-based polymers are generally referred to in the art as EP or EPDM polymers. Dienes suitable for use in the preparation of such polymers, especially multiblock polymers of EPDM type, include conjugated or unconjugated, straight or branched chain, cyclic or polycyclic dienes comprising from 4 to 20 carbon atoms. Preferred dienes include 1,4-pentadiene, 1,4-hexadiene, 5-ethylidene-2-norbornene, dicyclopentadiene, cyclohexadiene and 5-butylidene-2-norbornene. A particularly preferred diene is 5-ethylidene-2-borbornene.

The polymers (homopolymers, copolymers, interpolymers and multiblock interpolymers) described herein have a flow rate, I2, of 0.01 to 2000 g / 10 minutes in some embodiments; from 0.01 to 1000 g / 10 minutes in other embodiments; from 0.01 to 500 g / 10 minutes in other embodiments; and from 0.01 to 100 g / 10 minutes in other embodiments. In some embodiments, the polymers can have a flow rate, I2, of 0.01 to 10 g / 10 minutes, 0.5 to 50 g / 10 minutes, 1 to 30 g / 10 minutes, 1 to 6 g / 10 minutes or 0.3 to 10 g / 10 minutes. In some embodiments, the flow rate of the polymers can be approximately 1 g / 10 minutes, 3 g / 10 minutes or 5 g / 10 minutes. In other embodiments, the polymers can have a flow rate greater than 20 dg / min; greater than 40 dg / min in other embodiments; and greater than 60 dg / min, in other embodiments.

The polymers described herein may have molecular weights, Mw, from 1,000 g / mol to 5,000,000 g / mol in some embodiments; from 1000 g / mol to 1,000,000 in other embodiments; from 10,000 g / mol to 500,000 g / mol in other embodiments; and from 10,000 g / mol to 300,000 g / mol in other embodiments. The density of the polymers described herein may be from 0.80 to 0.99 g / cm 3 in some embodiments; for polymers containing ethylene from 0.85 g / cm3 to 0.97 g / cm3. In some embodiments, the density of the ethylene / aolefin polymers may be in the range of 0.860 to 0.925 g / cm 3 or 0.867 to 0.910 g / cm 3.

In some embodiments, the polymers described herein may have a tensile strength greater than 10 MPa; a tensile strength 11MPa in other embodiments; and a tensile strength � 13 MPa in other embodiments. In some embodiments, the polymers described herein may have an elongation at break of at least 600 percent at a crosshead separation rate of 11 cm / minute; at least 700 percent in other embodiments; at least 800 percent in other embodiments; and at least 900 percent in other embodiments.

In some embodiments, the polymers described herein may have a ratio of storage modules, �� (25 ° C) / �� (100 ° C), from 1 to 50; from 1 to 20 in other embodiments; and from 1 to 10 in other embodiments. In some embodiments, the polymers may have a permanent compression strain at 70 ° C of less than 80 percent; less than 70 percent in other embodiments; less than 60 percent in other embodiments; and less than 50 percent, less than 40 percent, to a permanent compression strain of 0 percent in other embodiments.

In some embodiments, ethylene / α-olefin interpolymers may have a heat of fusion of less than 85 � / g. In other embodiments, the ethylene / α-olefin interpolymer may have a resistance to granule blocking equal to or less than 4800 Pa; equal to or less than 2400 Pa in other embodiments; equal to or less than 240 Pa, and as low as 0 Pa in other embodiments.

In some embodiments, block polymers prepared with two catalysts that incorporate different amounts of comonomer, may have a weight ratio of the blocks thus formed in the range of 95: 5 to 5:95. In some embodiments, the elastomeric interpolymers have an ethylene content of 20 to 90 percent, a diene content of 0.1 to 10 percent, and an a-olefin content of 10 to 80 percent, based on weight total polymer. In other embodiments, multi-block elastomeric polymers have an ethylene content of 60 to 90 percent, a diene content of 0.1 to 10 percent and an a-olefin content of 10 to 40 percent, based on weight total polymer. In other embodiments, the interpolymer can have a Mooney viscosity (ML (1 + 4) 125 ° C) in the range of 1 to 250. In other embodiments, said polymers can have an ethylene content of 65 to 75 percent, a diene content of 0 to 6 percent and an olefin content of 20 to 35 percent.

In some embodiments, the polymer may be a propylene-ethylene copolymer or interpolymer having an ethylene content between 5 and 20% by weight and a flow rate (at 230 ° C with 2.16 kg weight) of 0, 5 to 300 g / 10 min. In other embodiments, the propylene-ethylene copolymer or interpolymer can have an ethylene content between 9 and 12% by weight and a flow rate (at 230 ° C with 2.16 kg weight) of 1 to 100 g / 10 min.

In some embodiments, the polymer is a copolymer or interpolymer based on propylene. In some embodiments, a propylene / ethylene copolymer or interpolymer is characterized by having essentially isotactic propylene sequences. The term "substantially isotactic propylene sequences", and similar expressions, refer to the sequences having an isotactic triad (mm) measured by 13 C NMR greater than about 0.85, preferably greater than about 0.90, more preferably greater than about 0.92 and most preferably greater than about 0.93 Isotactic triads are well known in the art and are described, for example, in US Patent 5,504,172 and document No. 00101745, which they refer to the isotactic sequence in terms of a triad unit in the molecular chain of the copolymer determined by 13 C NMR spectra. In other particular embodiments, the ethylene-olefin copolymer can be copolymers or interpolymers of ethylene-butene, ethylene- hexene, or ethylene-octene In other particular embodiments, the propylene-a-olefin copolymer may be a copolymer or interpolymer of propylene-ethylene or propylene-ethylene-butene.

The polymers described herein (homopolymers, copolymers, interpolymers, multiblock interpolymers) can be prepared using a single site catalyst and can have a weighted average molecular weight of about 15,000 to about 5 million, such as about 20,000 to about 1 million The molecular weight distribution of the polymer can be from about 1.01 to about 80, such as from about 1.5 to about 40, such as from about 1.8 to about 20.

The resin may also have a relatively low melting point in some embodiments. For example, the melting point of the polymers described herein may be less than about 160 ° C, such as less than 130 ° C, such as less than 120 ° C. For example, in one embodiment, the melting point may be less than about 100 ° C; in another embodiment, the melting point may be less than about 90 ° C; less than 80 ° C in other embodiments; and less than 70 ° C in other embodiments. The glass transition temperature of the polymeric resin can also be relatively low. For example, the glass transition temperature may be less than about 50 ° C, such as less than about 40 ° C.

In some embodiments, the polymer may have a Shore A hardness of 30 to 100. In other embodiments, the polymer may have a Shore A hardness of 40 to 90; from 30 to 80 in other embodiments; and from 40 to 75 in other embodiments.

Polymers, copolymers, interpolymers and multi-block olefinic interpolymers can be functionalized by incorporating at least one functional group in their polymer structure. Examples of functional groups may include, for example, ethylenically unsaturated mono-and di-functional carboxylic acids, anhydrides of ethylenically unsaturated mono-and di-functional carboxylic acids, their salts and esters. Said functional groups may be grafted into an olefinic polymer, or they may be copolymerized with ethylene and an optional additional comonomer to form an ethylene interpolymer, the functional comonomer and optionally another comonomer (s). The means for grafting functional groups in polyethylene are described, for example, in patents.

No. 4,762,890, 4,927,888 and 4,950,541. A particularly useful functional group is maleic anhydride.

The amount of functional group present in the functional polymer may vary. The functional group may be present in an amount of at least about 1.0 percent by weight, in some embodiments; at least about 5 percent by weight in other embodiments; and at least about 7 percent by weight in other embodiments. The functional group may be present in an amount less than about 40 percent by weight, in some embodiments; less than about 30 percent by weight in other embodiments; and less than about 25 percent by weight in other embodiments.

Additives

Additives and adjuvant can be included in any of the formulations comprising polymers, copolymers, interpolymers and multiblock interpolymers described above. Suitable additives include fillers, such as organic and inorganic particles, including clays, talc, titanium dioxide, zeolites, powdered metals, organic and inorganic fibers, including carbon fibers, silicon nitride fibers, wire or steel net and nylon or polyester cord, nanoparticles, clays, etc .; tackifiers, diluting oils, including paraffinic or naphthalenic oils; and other natural and synthetic polymers, including other polymers in accordance with the embodiments of the invention. The thermoplastic compositions according to other embodiments of the invention may also contain organic or inorganic fillers or other additives, such as starch, talc, calcium carbonate, glass fibers, polymeric fibers (including nylon, rayon, cotton, polyester and polyamide) , fibers, flakes or metal particles, silicates in expandable layers, phosphates or carbonates, such as clays, mica, silica, alumina, aluminosilicates or aluminophosphates, carbon filaments, carbon fibers, nanoparticles including nanotubes, wolastonite, graphite, zeolites and ceramics , such as silicon carbide, silicon nitride or titania. Silane-based agents or other coupling agents can also be used for a better charge bond.

Suitable polymers for mixing with the polymers described above include thermoplastic and non-thermoplastic polymers, including natural and synthetic polymers. Example polymers for mixing include ethylene-vinyl acetate (EVA) copolymers, ethylene / vinyl alcohol, polystyrene, modified impact polystyrene, ABS, styrene / butadiene block copolymers and their hydrogenated derivatives (SBS and SEBS), and thermoplastic polyurethanes.

Suitable conventional block copolymers that can be mixed with the polymers described herein may have a Mooney viscosity (ML 1 + 4 at 100 ° C) in the range of 10 to 135, in some embodiments; from 25 to 100 in other embodiments; and from 30 to 80 in other embodiments. Suitable polyolefins especially include linear or low density polyethylene, polypropylene (including its atactic, isotactic, syndiotactic and modified impact versions) and poly (4-methyl-1-pentene). Suitable styrene polymers include polystyrene, rubber modified polystyrene (HIPS), styrene / acrylonitrile copolymers (SAN), rubber modified SAN (ABS or AES) and maleic anhydride copolymers and styrene.

The mixtures can be prepared by mixing or kneading the respective components at a temperature approximately equal to or greater than the melting temperature of one or both components. For most multi-block copolymers, this temperature may be above 130 ° C, most generally above 145 ° C and most preferably above 150 ° C. Typical equipment may be used to mix or knead the polymer that is able to reach the desired temperatures and melt plasticizing the mixture. These include mills, kneaders, extruders (both by a single screw and by two screws), Banbury� mixers, calenders and the like. The sequence and mixing procedure may depend on the final composition. A combination of Banbury batch mixers and continuous mixers can also be used, such as a Banbury mixer followed by a mixer mill followed by an extruder. Typically, a TPE or TPV composition will have a higher crosslinkable polymer charge (typically the conventional block copolymer containing unsaturations) compared to the TPO compositions. Generally, for TPE and TPV compositions, the weight ratio between the block copolymer and the multi-block copolymer may be in the range of about 90:10 to 10:90, more preferably 80:20 to 20:80 and more preferably from 75:25 to 25:75. For TPO applications, the weight ratio between the multi-block copolymer and the polyolefin may be from about 49:51 to about 5:95, more preferably from 35:65 to about 10:90. For applications of modified styrene polymers, the weight ratio between the multi-block copolymer and the polyolefin may also be from about 49:51 to about 5:95, more preferably from 35:65 to about 10:90. The ratios can be changed by varying the viscosity ratios of the different components. There is a considerable bibliography that illustrates techniques for changing phase continuity by changing the viscosity ratios of the constituents of a mixture and a person skilled in the art can consult it if necessary.

The mixed compositions may contain processing oils, plasticizers and processing aids. Rubber processing oils that have a given ASTM designation and paraffinic, naphthalenic or aromatic processing oils are all suitable for use. In general, from 0 to 150 parts, more preferably from 0 to 100 parts, and most preferably from 0 to 150 can be used.

50 parts of processing oils, plasticizers and / or processing aids per 100 parts of total polymer. Larger amounts of oil may have a tendency to improve the processing of the resulting product at the expense of some physical properties. Additional processing aids include conventional waxes, salts of fatty acids, such as calcium stearate or zinc stearate, (poly) alcohols including glycols, ethers of (poly) alcohols, including glycolic ethers, (poly) esters, including (poly ) glycolic esters and metal salts, especially salts of group 1 6 2 or zinc metals, derived therefrom.

For conventional TPO, TPV and TPE applications, carbon black is a useful additive for UV absorption and stabilizing properties. Representative examples of carbon blacks include ASTM N110, N121, N220, N231, N234, N242, N293, N299, S315, N326, N330, M332, N339, N343, N347, N351, N358, N375, N539, N550, N582 , N630, N642, N650, N683, N754, N762, N765, N774, N787, N907, N908, N990 and N991. These carbon blacks have iodine absorptions in the range of 9 to 145 g / kg and average pore volumes ranging from 10 to 150 cm3 / 100 g. Generally, carbon blacks of smaller particle sizes are used to the extent permitted by cost considerations. For many of these applications the present polymers and mixtures thereof require little or no amount of carbon black, thus allowing considerable freedom of design to include alternative pigments or no pigment at all.

The compositions, including thermoplastic mixtures according to the embodiments of the invention, may also contain anti-ozone agents and antioxidants that are known to those skilled in the chemistry of rubbers. Anti-ozone agents can be physical protectors, such as brain materials that reach the surface and protect this part of oxygen or ozone or they can be chemical protectors that react with oxygen or ozone. Suitable chemical protectors include styrene phenols, butylated octyl phenol, butyl di (methylbenzyl) phenol, p-phenylenediamines, butylated reaction products of p-cresol and dicyclopentadiene (DCPD), polyphenylic antioxidants, hydroquinone derivatives, quinoline, diphenylene antioxidants , thioester antioxidants and mixtures thereof. Some representative trademarks of such products are antioxidant �ingstayT S, antioxidant PolystayT 100, antioxidant PolystayT 100 AZ, antioxidant PolystayT 200, antioxidant �ingstayT L, antioxidant �ingstayT LHLS, antioxidant �ingstayT K, antioxidant �ingstayT 29, antioxidant �ingstayT SN -1 and antioxidants IrganoxT. In some applications, the antioxidants and anti-ozone agents used will preferably be non-colored and non-migratory.

To provide additional stability against UV radiation, light stabilizers against hindered amines (HALS) and UV absorbers can also be used. Suitable examples include TinuvinT 123, TinuvinT 144, TinuvinT 622, TinuvinT 765, TinuvinT 770 and TinuvinT 780, available from Ciba Specialty Chemicals, and ChemisorbT T944, available from Cytex Plastics, Houston TX, United States. A Lewis acid with an HALS compound may be additionally included in order to obtain a superior surface quality, as described in US Patent No. 6,051,681. Other embodiments may include a thermal stabilizer, such as IR�ANOXT PS 802 FL, for example.

For some compositions an additional mixing process can be used to previously disperse thermal stabilizers, antioxidants, anti-ozone agents, carbon black, UV absorbers and / or light stabilizers to form a masterbatch and subsequently form the mixtures. polymeric from them.

Suitable crosslinking agents (also referred to as curing or vulcanizing agents) for use herein include sulfur based compounds, peroxide base or phenolic base. Examples of the above materials are found in the art, including those described in U.S. Patent Nos. 3,758,643, 3,806,558, 5,051,478, 4,104,210, 4,130,535, 4,202,801, 4,271,049, 4,340,684 , 4,250,273, 4,927,882,

4,311,628 and 5,248,729.

When sulfur-based curing agents are used, curing accelerators and activators can also be used. Accelerators are used to control the time and / or temperature necessary for dynamic vulcanization and to improve the properties of the crosslinked article obtained. In one embodiment, a single accelerator or primary accelerator is used. The primary accelerator (s) may be used in total amounts in the range of about 0.5 to about 4, preferably about 0.8 to about 1.5 phr, based on the total weight of the composition. In another embodiment, combinations of a primary and a secondary accelerator can be used, the secondary accelerator being used in smaller amounts, such as from about 0.05 to about 3 phr, in order to activate and improve the properties of the cured article. Accelerator combinations generally produce items that have properties that are somewhat better than those produced using a single accelerator. In addition, delayed-acting accelerators can be used that are not affected by normal processing temperatures and also produce satisfactory cure at ordinary vulcanization temperatures. Vulcanization retarders can also be used. Suitable types of accelerators that can be used in the present invention are amines, disulfides, guanidines, thioureas, thiazoles, thiouramas, sulfenamides, dithiocarbamates and xanthates. Preferably, the primary accelerator is a sulfenamide. If a second accelerator is used, the secondary accelerator is preferably a compound of guanidine, dithiocarbamate or thiourama. Some processing aids and curing activators, such as stearic acid and ZnO, can also be used. When peroxide-based curing agents are used, co-activators or co-agents may be used in combination with them. Suitable coagents include trimethylolpropane triacrylate (TMPTA), trimethylolpropane trimethacrylate

(TMPTMA), triallyl cyanurate (TAC) and triallyl isocyanurate (TAIC), among others. The use of peroxide crosslinking agents and optional co-agents used for partial or complete dynamic vulcanization is known in the art and is described for example in the publication "Peroxide Vulcanization of Elastomer", Vol. 74, No. 3, August-August 2001

When the polymeric composition is at least partially crosslinked, the degree of crosslinking can be measured by dissolving the composition in a solvent for a certain time and calculating the percentage of gel or non-removable component. The percentage of gel generally increases with increasing levels of crosslinking. For articles cured according to the embodiments of the invention, the percentage gel content is suitably in the range of 5 to 100 percent.

In some embodiments, the additives may also include perfumes, algae inhibitors, antimicrobial and antifungal agents, flame retardants and halogen-free flame retardants, as well as slip and anti-block additives. Other embodiments may include PDMS to reduce the abrasion resistance of the polymer. The adhesion of the polymer to the sand can also be improved by the use of adhesion promoters or functionalization or coupling agents of the polymer with organosilane, polychloroprene (neoprene) or other grafting agents.

Polymer Coated Particles

As described above, sands or other particulate materials may be coated or incorporated with one or more layers of a polymer or polymer mixture. The polymer and particulate materials can be incorporated, in one embodiment, by mixing a thermoplastic polymer with a particulate substrate to form a mixture at a temperature greater than the melting point of the thermoplastic polymer.

In one embodiment, the polymer and particulate materials may be incorporated by first heating the particulate material to be coated at a high temperature first. Then, the particulate material can be fed to a mixer, which can continuously stir and disperse the contents of the mixer.

Then a polymer or polymer mixture, as described above, can be added to the mixer. The amount of polymer added to the mixer can be based on the amount of particulate material to be coated, and the desired level of coating on the particles. Stirring should be sufficient to evenly distribute the polymer completely, uniformly coating the particles with the polymer.

The temperature of the previously heated particles may be sufficient to melt at least a part of the polymer. The particulate material can be preheated to a temperature between about 60OC and 350OC, in some embodiments, where the temperature can be based on the amount of polymer added and the melting point of the polymer. In other embodiments, the sand or other particulate materials may be preheated to a temperature between about 140 ° C and 350 ° C; between about 80 ° C and 270 ° C, in other embodiments; and between about 150 ° C and 250 ° C, in other embodiments. In some embodiments, the particulate material may be heated to a temperature less than 199 ° C; less than 195 ° C, in other embodiments; less than 190 ° C, in other embodiments; less than 180 ° C, in other embodiments; less than 170 ° C, in other embodiments; and less than 160 ° C, in other embodiments. In other embodiments, a mixture of the particulate substrate and the polymer or polymers can be heated to the temperatures described above.

Then, the coated particles can be cooled to a temperature below the melting point of the polymer by indirect heat exchange or by direct heat exchange, such as by injecting water and / or air into the mixture, after which particles can be collected for use as filler or in other suitable applications. Any agglomerates formed during the coating process can be separated from the good creep material by sieving the particles, and the agglomerates can be discarded or can be deagglomerated for use as filler.

In some embodiments, the polymer or polymer blend may include one or more of the polymers described above, including: homopolymers, copolymers, interpolymers and multiblock interpolymers, based on propylene; homopolymers, copolymers, interpolymers and multiblock interpolymers, based on ethylene; and their combinations In some embodiments, the thermoplastic polymer coating may contain a polyolefin having a melting point of 100 ° C or less. In other embodiments, the thermoplastic polymer coating may contain a polyolefin having a melting point of 70 ° C or less.

In some embodiments, the coated particles may have a dry polymer content in the range of 1 percent by weight to 15 percent by weight. In other embodiments, the coated particles may have a dry polymer content in the range of 2 percent by weight to 13 percent by weight; from 3 percent by weight to 10 percent by weight, in other embodiments; from 4 percent by weight to 8 percent by weight, in other embodiments; and from 5 percent by weight to 7 percent by weight, in other embodiments. In other embodiments, the coated particles may have a dry polymer content greater than 5 percent by weight; greater than 7 percent by weight, in other embodiments; greater than 8 percent by weight, in other embodiments; and greater than 10 percent by weight, in other embodiments. Each of the above weight fractions is based on the combined weight of the particulate substrate (mineral grains, sand, etc.) and the polymer.

As described above, in some embodiments, the thermoplastic polymer may be a mixture of two or more thermoplastic polymers. In some embodiments, the mixture of thermoplastic polymers may contain at least two thermoplastic polymers having melting points that differ by at least 5 ° C. In other embodiments, the mixture of thermoplastic polymers may contain at least two thermoplastic polymers having melting points that differ by at least 10 ° C; at least 15 ° C, in other embodiments; and at least 20 ° C, in other embodiments. In other embodiments, the mixture of thermoplastic polymers may contain at least two thermoplastic polymers having a flow rate, I2, which differs by at least 3 dg / min; in at least 5 dg / min, in other embodiments; at least 10 dg / min, in other embodiments; in at least 20 dg / min, in other embodiments.

In the embodiment in which a multi-layer coating is desired, a first polymer coating or polymer blend can be applied as described above, such as mixing the first polymer with the particulate substrate at a temperature greater than the point of polymer fusion. Again, the substrate can be preheated to the desired temperature or the polymer-substrate mixture can be heated to a temperature greater than the melting point of the first polymer. Then, the polymer can be dispersed by stirring, uniformly coating the substrate in particles. Then, the coated particles can be cooled to a temperature below the melting point of the first polymer, using water and / or air. The coated particles can then be coated with a second polymer or polymer mixture, where the second polymer has a melting point less than the melting point of the coating layer of the first polymer.

In some embodiments, the coated particles are cooled to a temperature lower than the melting point of the first polymer, but greater than the melting point of the second polymer. In other embodiments, the coated particles obtained from the first coating can be reheated to a temperature greater than the melting point of the second polymer but less than the melting point of the first polymer. Then, the coated particles can be mixed with the second thermoplastic polymer, melting at least a part of the second polymer. The second polymer can then be distributed by a mixer, forming a uniform coating on the particles. The mixture can then be cooled to a temperature lower than the melting point of the first polymer, returning to a good creep particulate material. Again, any formed agglomerate can be separated by screening, if desired.

In multi-layer embodiments, the first polymer has a melting point greater than the second polymer. For example, in some embodiments, the first polymer may have a melting point greater than about 95 ° C and the second polymer may have a melting point less than the melting point of the first polymer. In other embodiments, the first polymer may have a melting point greater than about 90 ° C and the second polymer may have a melting point between about 50 ° C and 90 ° C. In other embodiments, the first polymer may have a melting point greater than about 120 ° C and the second polymer may have a melting point between about 60 ° C and 110 ° C.

In some embodiments, the first polymer may have a melting point at least 5 ° C greater than the melting point of the second polymer. In other embodiments, the first polymer may have a melting point at least 10 ° C greater than the melting point of the second polymer. at least 15 ° C higher, in other embodiments; and at least 20 ° C, in other embodiments.

The specific combination of polymers and melting points will determine the appropriate temperatures for the steps noted above to form a particle coated with multiple layers. For example, when the first polymer has a melting point of about 100 ° C and the second polymer has a melting temperature of about 70 ° C, the particulate substrate can be heated to a temperature of at least 120 ° C to coat the substrate in particles with the first polymer. Then, the mixture can be cooled, reheated or maintained at a temperature between 70 ° C and 100 ° C to coat the substrate in particles with the second polymer.

In multi-layer embodiments, the coated particles may have a total polymer content in the range of 1 percent by weight to 30 percent by weight. In other embodiments, the coated particles may have a total polymer content in the range of 1 percent by weight to 20 percent by weight; from 2 percent by weight to 15 percent by weight, in other embodiments; from 3 percent by weight to 12 percent by weight, in other embodiments. Each of the above weight fractions is based on the combined weight of the particulate substrate (mineral grains, sand, etc.) and each of the polymer layers (the first polymer layer, second polymer, third polymer, etc.). ).

In multi-layer embodiments, the coated particles may have a dry inner layer of a first polymer in the range of 1 percent by weight to 15 percent by weight. In other embodiments, the coated particles may have a dry inner layer content in the range of 2 percent by weight to 9 percent by weight; from 3 percent by weight to 8 percent by weight, in other embodiments; from 4 percent by weight to 7 percent by weight, in other embodiments. The coated particles may have a dry outer layer of a second polymer in the range of 1 percent by weight to 15 percent by weight. In other embodiments, the coated particles may have a dry outer layer content in the range of 2 percent by weight to 8 percent by weight; from 3 percent by weight to 5 percent by weight, in other embodiments. Each of the fractions in

Previous weight is based on the combined weight of the particulate substrate (mineral grains, sand, etc.) and the first polymer and the second polymer.

As described above, in some embodiments, the first thermoplastic polymer or the second thermoplastic polymer may be a mixture of two or more polymers. In some embodiments, the mixture of thermoplastic polymers may contain at least two thermoplastic polymers having melting points that differ by at least 5 ° C. In other embodiments, the mixture of thermoplastic polymers may contain at least two thermoplastic polymers having melting points that differ by at least 10 ° C; at least 15 ° C, in other embodiments; and at least 20 ° C, in other embodiments. In other embodiments, the mixture of thermoplastic polymers may contain at least two thermoplastic polymers having a flow rate, I2, which differs by at least 3 dg / min; in at least 5 dg / min, in other embodiments; at least 10 dg / min, in other embodiments; in at least 20 dg / min, in other embodiments.

In some embodiments, a polymeric coating can be applied as described above. The polymeric coating can subsequently be foamed, resulting in a particle that has improved softness. In several embodiments, the first polymer layer, the second polymer layer, or both polymer layers can be foamed. For example, a second polymer coating can be applied on the first foamed layer, where the second polymer has a lower melting point than the foamed polymer.

In yet other embodiments, the particulate substrate may be coated with three or more layers of polymers. The melting point of the polymer used in each successive layer must be less than the melting point of the polymer layer to be coated.

In some embodiments, the first polymer layer, the second polymer layer, or both can be crosslinked. For example, in some embodiments, the first polymer layer can be crosslinked before coating the substrate in particles with the second polymer. In other embodiments, the second polymer can be crosslinked after forming the second coating layer on the particulate substrate.

Stirring should be sufficient to evenly distribute the polymers completely, uniformly coating the particles with the polymers used. In some embodiments, the polymer or polymers (first polymer layer, second polymer layer, or both) can coat at least 50 percent of the surface of the particulate substrate. In other embodiments, the polymer or polymers can coat at least 60 percent of the surface of the substrate in particles; at least 70 percent, in other embodiments; at least 80 percent, in other embodiments; and at least 90 percent, in other embodiments. In some embodiments, the extent of the coating can be observed by visual examination with a microscope, by changes in the overall color of the substrate in particles, or by measuring the gain / loss of weight and / or particle packing density. For example, when the polymer coating is one color and the particle substrate is another, a visual inspection of the particles can provide a means to assess the percentage of coating.

In some embodiments, the coated particles described above can be used as filler in a synthetic grass. The deformation of a synthetic grass system after a long period of use may depend on the height of the pile, the density of the plumes and the resistance of the thread. The type and volume of the filler material can also significantly influence the deformation resistance of the artificial grass. The Lisport test can be used to analyze wear behavior, and is useful for designing an effective artificial grass system. In addition, tests can be carried out to analyze the behavior with temperature and aging, as well as the rebound and spin properties of the resulting artificial grass. With respect to each of these properties, the artificial grass that contains the filling materials described above can meet FIFA's specifications for the use of artificial grass on soccer fields (see, for example, "February 2005 FIFA �uality Concept Requirements for Artificial Turf Surfaces, "FIFA's manual of test methods and requirements for artificial turf for soccer, which is incorporated entirely by reference herein.

The embodiments of the polymer coated substrates described herein may have a color change, in accordance with the EN ISO 20105-A02 test method, greater than or equal to 3 in the gray scale. Other embodiments of the polymer-coated substrates can meet FIFA's requirements for particle size, particle shape and bulk density, tested using test methods EN 933 -Part 1, prEN 14955, and EN 13041, respectively. Polymer coated substrates can also meet the requirements of DIN V 18035-7-2002-06 for environmental compatibility.

EXAMPLES

Example 1

Sand having a particle size in the range of 0.3 to 0.7 mm was coated with two layers of polyethylenes stabilized against UV light as described above. The total polymer content of the coated sand was 6.5 percent by weight, based on the weight of the dry sand. The UV light stabilizer was used in an amount of 0.5 percent by weight of the polymer.

A Lisport test was carried out on the artificial grass using the coated sand of example 1 as filler. The artificial grass included an elastic layer of 16 mm foamed polyethylene. The test results indicated excellent wear resistance and there was no sand compaction. After the Lisport test, the filling remained loose and with easy movement. The padding also met the classification of the FIFA 2-star tests, maintaining good shock absorption, vertical deformation, bouncing of the ball and rotational resistance after wear. The filling also maintained good drainage.

Some dust was generated in the closed environment of the Lisport test, which simulated wear over 5 years. However, some dust generation during the wear test does not affect the aesthetic properties of the artificial grass and padding due to the routine cleaning or washing of the carpet during normal use.

Polymer coated sands produced as described herein may be useful as a filler material for artificial football and sports surfaces, among other applications. Advantageously, the embodiments described herein can provide a polymer coated sand having a homogeneous and uniform coating, good heat and slip resistance, as well as good haptic and aesthetic. In particular, the embodiments described herein may provide a superior balance of these properties compared to the prior art filler, including one or more of: better color retention, better resilience and wear resistance, better heat resistance, better stability of the artificial grass at lower load levels, better flexibility and smoothness, and lower cost.

Embodiments using a low melting point polymer, such as AFFFNITYT �A, alone or in combination with other polyolefins in one or more layers, can provide a very uniform and homogeneous coating, resulting in a softer surface on the padding, resulting in superior wear resistance, good haptic and aesthetic and excellent safety for the player. The use of a low melting point polymer can also advantageously reduce the requirements of heating and cooling, reducing the energy requirements in the process, and resulting in a faster time cycle per batch.

Embodiments of the polymer-coated substrates described herein may also be useful in applications that include rotomolded soft items, sustaining agents, fillers for other artificial grass applications, such as golf courses and gardens, and in use. in heavy layers to dampen noise and vibrations, among others.

Other embodiments described herein provide a greater coating weight and a wider choice of polymeric materials in terms of composition and molecular weight, allowing softer materials to be used that result in improved damping characteristics. For example, the flow rate of the polyolefins described herein is not limited. The softer materials produced may result in a longer abrasion resistance due to the decrease in surface roughness.

Claims (14)

1. A particulate material comprising:

-

a particulate substrate coated with a first layer comprising a first thermoplastic polymer and a second layer comprising a second thermoplastic polymer;

-

wherein the melting point of the first thermoplastic polymer is greater than the melting point of the second thermoplastic polymer.

2.

The particulate material of claim 1, wherein the first thermoplastic polymer is selected from homopolymers, copolymers, interpolymers and multiblock interpolymers based on propylene; homopolymers, copolymers, interpolymers and multiblock interpolymers, based on ethylene; and their combinations

3.

The particulate material of claim 1, wherein the particulate substrate is selected from mineral grains, sands and rubber particles

Four.

The particulate material of claim 3, wherein the particulate substrate is a silica-based sand.

5.

The particulate material of claim 1, wherein the second thermoplastic polymer is selected from: homopolymers, copolymers, interpolymers and multiblock interpolymers, based on propylene; homopolymers, copolymers, interpolymers and multiblock interpolymers, based on ethylene; and their combinations

6.

The particulate material of claim 1, wherein the melting point of the second thermoplastic polymer is 100 ° C or less.

7.

The particulate material of claim 1, wherein the first thermoplastic polymer, the second thermoplastic polymer, or both, have been foamed.

8.

The particulate material of claim 1, which further comprises an adhesion promoter.

9.

The particulate material of claim 1, wherein the particulate material comprises the first polymer in an amount in the range of 1 to 15 percent by weight, and the second polymer in an amount in the range of 1 to 15 per weight percent, with respect to the combined weight of the particulate substrate, the first thermoplastic polymer and the second thermoplastic polymer.

10.

The particulate material of claim 1, wherein the particulate material comprises a total polymer content of 1 to 20 percent by weight, based on the combined weight of the particulate substrate, the first thermoplastic polymer and the second thermoplastic polymer .

eleven.

The particulate material of claim 1, wherein the first thermoplastic polymer has a melting point at least 5 ° C greater than the melting point of the second polymer.

12.

The particulate material of claim 1, wherein the first thermoplastic polymer, the second thermoplastic polymer, or both, have a flow rate greater than 40 g / 10 min.

13.

The particulate material of claim 1, wherein the first thermoplastic polymer covers at least 50% of the surface of the particulate substrate.

14.

Artificial grass comprising the particulate material of claim 1.